It might glide, but not fly, for the same reason that you can't even if we give you wings, the size is all wrong and you don't have the necessary muscles.
–
terdonJul 18 '13 at 17:42

Over time, could the spider evolve the "muscles" and movement in order to sustain flight with these web-wings?
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lonewookieJul 18 '13 at 17:44

Perhaps but it would no longer be a spider. Your question asks whether a spider could fly without changing its morphology, just by spinning webs between its legs. If you allow it to change form then sure it could, just make it morph into an eagle.
–
terdonJul 18 '13 at 17:46

I gotcha. In the short term the most a spider could do with this is possibly glide. In the long-term it could gain flight but would be very different than any spider you see today.
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lonewookieJul 18 '13 at 17:50

3 Answers
3

It takes more than wings to fly, just look at the poor penguins. The first problem is that simply weaving webs between a spider's legs would probably not generate enough lift to keep her airborne. Flying creatures have a specific body plan that allows them to fly, if you just add a couple of wings to a hippopotamus it won't be able to fly.

On top of that, the spider would not have the necessary muscles to enable it to flap these wings even if they were capable of producing sufficient lift.

While it is theoretically possible (I stress theoretically) for a spider species to adapt over time (long long time) into a flying form, then it would no longer be a spider. So, in answer to your question, no, it is not possible.

almost anything is possible, jumping spiders move extremely quickly for their scale, and you could easily imagine an evolutionary pathway... spiders already use parachutes: the parachute gets bigger, the line get shorter and controlled by the rear most legs...

maybe it has already happened, there likely wouldn't be any fossil record of it, and spiders have been around for a long time (compared to apes).